Double clicking on the Control shortcut and nothing is happening.
When you run Control, one of the first thing that it does is look for other copies of Control already running. If so, it sends a message for the copy of Control to open a new login window and then the new copy terminates.
If Control gets hung while in the process of shutting down, it may be off the screen but still running in the background. When this happens and a new copy of Control is run, it may send a message to the old copy of Control running to open a new login. Since the old copy is hung, nothing seems to happen.
Normal. User is down on that client.
The Control process may be hung in the background already.